Earpiece voice rendering
 

I've come to N9 from the E72 and the E6 experience and I've found that the earpiece voice rendering of the N9 is a bit more shrill, which is fatiguing when you have lots of calls.

So I was wondering if there's a way to modify its rendering. I've found a blog article on the possibility to modify the volume, via alsamixer. Is there any way to "equalize" the sound? I'd like to reduce the most acute part..

Thanks